QODBC (or any Intuit QuickBooks SDK-based application) does not require credentials to connect to the QuickBooks company file. Connection authentication is performed by QuickBooks based on the Integrated application certificate stored in the QuickBooks company file.
If you must provide credentials in your application to connect to the ODBC driver, you can provide any username and password.
Example
username: admin
password: anything
username: administrator
password: somerandomtext